<i>Research Note</i>Supersolar metal abundances and the Broad Line Region of Narrow-line Seyfert 1 galaxies

Komossa, Stefanie; Mathur, S.

doi:10.1051/0004-6361:20010819

Cited by 27 publications

(34 citation statements)

References 36 publications

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“…There are several indications that NLS1 galaxies have supersolar metallicities (e.g., Mathur 2000; Komossa & Mathur 2001;Nagao et al 2002;Shemmer & Netzer 2002;Romano et al 2004;Fields et al 2005). We already noted in x 6 that those objects with reliable [O iii] k4363 measurements do not indicate enhanced temperatures in the low-density objects.…”

Section: Supersolar Metallicities and Temperature Effectsmentioning

confidence: 68%

The Narrow‐Line Region of Narrow‐Line and Broad‐Line Type 1 Active Galactic Nuclei. I. A Zone of Avoidance in Density

Komossa

Zhou

et al. 2007

ApJ

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The properties of narrow-line Seyfert 1 (NLS1) galaxies, the links and correlations between them, and the physics behind them, are still not well understood. Apart from accretion rates and black hole masses, density and outflows were speculated to be among the main drivers of the NLS1 phenomenon. Here we utilize the diagnostic power of the [S ii] kk6716,6731 intensity ratio to measure the density of the narrow-line region (NLR) systematically and homogeneously for a large sample of NLS1 galaxies, and we perform a comparison with a sample of broad-line type 1 active galactic nuclei (AGNs). We report the discovery of a ''zone of avoidance'' in density in the sense that AGNs with broad lines [FWHM(H ) > 2000 km s À1] avoid low densities, while NLS1 galaxies show a wider distribution in the NLR density, including a significant number of objects with low densities. A correlation analysis further shows that the Eddington ratio L/L Edd anticorrelates with density. We investigate a number of different models for the zone of avoidance in density. Supersolar metallicities and temperature effects, a strong starburst contribution in NLS1 galaxies, different NLR extents, and selective obscuration are considered unlikely. Possible differences in the fraction of matter-bounded clouds, and differences in the interstellar media of the host galaxies of NLS1 galaxies and broad-line Seyfert 1 ( BLS1) galaxies, can only be tested further with future observations. We tentatively favor the effects of winds/outflows, stronger in NLS1 galaxies than in BLS1 galaxies, to explain the observations.

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Section: Supersolar Metallicities and Temperature Effectsmentioning

confidence: 68%

The Narrow‐Line Region of Narrow‐Line and Broad‐Line Type 1 Active Galactic Nuclei. I. A Zone of Avoidance in Density

Komossa

Zhou

et al. 2007

ApJ

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“…Another interesting thing about the dotted curve is that it shows a monotonic rise in pressure with temperature; it has no equilibrium zone where components of different temperatures can exist in pressure balance with each other. Such behavior is seen in sources with steep soft X-ray spectra (e.g., NGC 4051; Komossa & Mathur 2001). Indeed, in Mrk 279, the continuum fit has a slope of À % 2, which may be the cause of the observed shape of the equilibrium curve.…”

Section: Properties Of the Warm Absorbermentioning

confidence: 91%

The Weak Absorbing Outflow in AGN Mrk 279: Evidence of Supersolar Metal Abundances

Fields

Mathur

Krongold

et al. 2007

ApJ

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We present analysis and photoionization modeling of the Chandra high-resolution spectrum of Mrk 279. There is clear evidence of an absorbing outflow that is best fit by a two-component model: one with a low-ionization parameter and one with a higher ionization parameter. The column density of the X-ray warm absorber, about log N H ¼ 20, is the smallest known of all active galactic nuclei (AGNs) in which X-ray absorbing outflows are observed. We find that the X-ray and UV/ FUV absorbers are part of the same overall outflow. There is some evidence of supersolar carbon, nitrogen, oxygen, and iron in the Chandra spectrum of Mrk 279. While this is not a robust result in itself, Chandra data in combination with the UV data and the pressure equilibrium between two phases of the outflow, support the scenario of supersolar abundances. This is the first case in which supersolar abundances are reported in the nucleus of a normal Seyfert galaxy. The data suggest that the outflow originates from a compact region around the nuclear black hole and that it carries insignificant amounts of mass and energy.

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“…Our main motivation in this paper is to improve on previous work (Hess, Kahn & Paerels 1997; Krolik, McKee & Tarter 1981; Reynolds & Fabian 1995; Komossa & Mathur 2001; Krolik & Kriss 2001; Rozanska, Kowalska & Goncalves 2008) by carrying out a systematic investigation of the stability curves and finally to give a quantitative handle on the relative stability nature of the WA as a function of the various physical parameters involved. In , we discuss the physical properties of the WA.…”

Section: Introductionmentioning

confidence: 99%

Properties of warm absorbers in active galaxies: a systematic stability curve analysis

Chakravorty

Kembhavi

Elvis

et al. 2009

Monthly Notices of the Royal Astronomical Society

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Signatures of warm absorbers are seen in soft X‐ray spectra of about half of all type 1 Seyfert galaxies observed and in some quasars and blazars. We use the thermal equilibrium curve to study the influence of the shape of the ionizing continuum, density and the chemical composition of the absorbing gas on the existence and nature of the warm absorbers. We describe circumstances in which a stable warm absorber can exist as a multiphase medium or one with continuous variation in pressure. In particular, we find the following results: (i) the warm absorber exists only if the spectral index of the X‐ray power‐law ionizing continuum α > 0.2 and has a multiphase nature if α∼ 0.8, which interestingly is the spectral index for most of the observed type 1 Seyfert galaxies; (ii) thermal and ionization states of highly dense warm absorbers are sensitive to their density if the ionizing continuum is sufficiently soft, i.e. dominated by the ultraviolet; (iii) absorbing gas with super‐solar metallicity is more likely to have a multiphase nature and (iv) the nature of the warm absorber is significantly influenced by the absence of iron and associated elements which are produced in the later stages of star formation history in Type Ia supernovae.

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Research NoteSupersolar metal abundances and the Broad Line Region of Narrow-line Seyfert 1 galaxies

Cited by 27 publications

References 36 publications

The Narrow‐Line Region of Narrow‐Line and Broad‐Line Type 1 Active Galactic Nuclei. I. A Zone of Avoidance in Density

The Narrow‐Line Region of Narrow‐Line and Broad‐Line Type 1 Active Galactic Nuclei. I. A Zone of Avoidance in Density

The Weak Absorbing Outflow in AGN Mrk 279: Evidence of Supersolar Metal Abundances

Properties of warm absorbers in active galaxies: a systematic stability curve analysis

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